The goal of the proposed research is to develop and evaluate a novel method of infant body volume and composition measurement. Body composition (% fat and fat-free mass) information is very important in the assessment of nutritional status and growth. Given the current lack of any suitable technology for this purpose, researchers and clinicians do not have access to this valuable information. The proposed methodology has been successfully developed and applied to the adult population, and has resulted in a commercially successful device marketed to universities and other customers interested in health care. The extension of the technology to infants is particularly challenging due special considerations and requirements specific to this young population. In particular, the high degree of precision and accuracy required for meaningful body composition determinations in very small infants is daunting. The applicant organization is highly experienced in this area, and has demonstrated excellent results with the Phase I engineering prototype. The proposed Phase II research will involve substantial technology development, special application to the infant population, interaction with a Scientific Advisory Board specific to the project, and thorough evaluation in a step- wise fashion beginning with inanimate phantoms and progressing to animals, and, lastly, infants. PROPOSED COMMERCIAL APPLICATION: The proposed research may lead to the development of a completely novel method of infant body composition measurement useful to researchers and physicians involved in infant nutritional assessment and growth. As medical technology advances, infants are increasingly viable at lower birth weights, creating a greater need to monitor body fat and lean tissue.